PROJECT SUMMARY/ABSTRACT Natural products, botanical supplements and even functional food products are inherently complex mixtures of secondary metabolites, with significant variability in structural characteristics and concentration present in the matrix. Their therapeutic efficacy is often based upon the combined action of combinations of constituents. Identifying bioactive metabolites from a mixture is a challenge, one which can be addressed through metabolomics approaches for screening and analyzing chromatographic fraction pools of natural products. To improve this data-driven approach, a more holistic approach to chromatography, and the pooling of fractions, is required. This project will develop an innovative statistical metric, the composite correlation, to improve on current statistical means of comparing similarities and differences in large datasets, and will be translated to optimize pooling methods and the subsequent biochemometric analysis. The proposed research project will also investigate the antimicrobial activities of metabolites from the medicinal lichen Usnea barbata and their effects on methicillin-resistant Staphylococcus aureus (MRSA) infections using a biochemometrics approach. Multicomponent mixtures which target both growth and quorum-sensing will be examined in their ability to limit host cellular damage as a result of infection. The heightened bioactivity will be demonstrated using a human epithelial (HaCaT) in vitro cell system further enable characterization of the complex interactions and combination effects that affect single or multiple mechanisms. These studies will also provide critical training in statistical modeling algorithms, analytical metabolomics and microbiological bioassays, and provide a foundation for beginning an independent research career.